In a sewer pipe having been buried under the ground for a long time, there arises a problem that the load carrying capacity is reduced to cause collapse of a road or the flow capacity becomes insufficient.
A method and an apparatus for solving such problem are disclosed in Patent Literatures 1 and 2.
A drainage pipe repairing apparatus described in Patent Literature 1 shown in FIG. 17 forms a new resin drainage pipe inside a deteriorated sewer pipe. With the drainage pipe repairing apparatus, a pipe body can be formed in an existing pipe in a simple manner, without using construction facilities for excavating earth.
In the case of the drainage pipe repairing apparatus, a resin pipe 50 (generally referred to as “corrugated pipe” or “waved pipe”) having flexibility is led out from a rotating drum 51, then inserted, through a manhole 52 on the left side, into an existing sewer pipe 53 from one side thereof, and then pulled in, by a winch 54, via a manhole 52 on the right side. In FIG. 17, the leading end of the resin pipe 50 has a cap 55 for the pulling-in, which is attached thereto, and the cap 55 has a wire 56 connected thereto.
In a pipeline restoration method described in Patent Literature 2, a restoration pipe formed from a thermoplastic material so as to have an outer diameter smaller than the inner diameter of a sewer pipe is pulled, through a manhole, into the sewer pipe to be restored. Then, hot air of 100° C. or higher is sent into the restoration pipe to be enclosed therein to an appropriate extent, whereby the restoration pipe is heated to have an enlarged diameter, thereby being brought into close contact of it with the inner wall of the sewer pipe.
The restoration pipe to be used in this pipeline restoration method is formed into a flatten shape in the diameter direction of the pipe when being pulled into the sewer pipe, and after the restoration pipe has been pulled into the sewer pipe, the shape of the restoration pipe is changed into a cylindrical shape with the hot air, and the diameter thereof is forcedly enlarged. In this manner, the restoration pipe is brought into close contact with the inner wall of the sewer pipe, whereby the inner wall of the sewer pipe can be lined.